1. Field of the Invention
The present invention relates to a handling method and a handling apparatus.
2. Description of the Related Art
With the recent development of semiconductor devices having a higher degree of integration, circuit patterns have been decreasing in size more and more. In producing such fine circuit patterns, the presence of dust poses a serious problem. Thus, in the manufacture of semiconductor devices, a great effort has been made to reduce dust in atmosphere.
Under the situation, the number of workers, which is closely related to the amount of dust, has been reduced as much as possible in the manufacture of semiconductor devices in a clean room. For example, handling apparatuses, to which robot techniques have been applied, are widely employed in handling semiconductor wafers, wafer boats, liquid-crystal display substrates, etc. In such handling apparatuses, for example, two hold arms provided with vacuum chucks hold semiconductor wafers, or two hold hands arranged with a distance hold both ends of a quartz wafer boat.
According to the study conducted by the inventors, serious problems occur in handling apparatuses which handle objects, such as semiconductor wafers, wafer boats, or liquid-crystal display substrates, in different steps, e.g. a CVD film forming step and a oxide film forming step, or a resist coating step and a developing step. Namely, a chemical or a product adheres to that part of the hold arm or hold hand which is put in contact with a object in a certain step. Then, the chemical or the product adheres to another object and contaminates the atmosphere of another step ("cross-contamination").